Dandy Dental

Deep into the Dandy Dental area, in the northwest corner, you'll find the Telekinesis plasmid which you should instantly swap into your arsenal (replacing the Incinerate! plasmid). You can test out the Telekinesis with the tennis ball machine in the hall behind you. The main thing you should learn is that the Telekinesis power uses no EVE energy unless you use it to throw items. That means you can use Telekinesis to pull items towards you and pick 'em up (or drop them) without wasting your meter.

Expect an enemy or two as you backtrack to the main foyer. Go to the hall that's under the watch of the last turret you hacked (due south) to find a doorway that's locked. If you look through the broken glass left of the door, you can use the Telekinesis power to pull towards you the key that's hanging on a pillar in the room beyond the door. Use the key to unlock the door leading to Chompers Dental.